Match the Python version of the deployment target

Symptom

A script that runs locally dies on the server with SyntaxError — a parse-time failure, so not a single line executes.

Cause

Shared hosting and older servers commonly default to 3.9. Your laptop is on 3.11-3.12.

Syntax	Requires
match / case	3.10+
union type hints	3.10+
tomllib	3.11+
itertools.batched	3.12+

Fix

• Run python3 -V on the server first
• ★ Versions differ per execution site even inside one project — the PaaS runtime and the SSH box being different is normal
• One parse pass at the lowest version catches it: python3.9 -m py_compile *.py

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